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9. METHOD OF EXAMINATION
Examination shall be done by continuous method in which current is applied
while the magnetic current remains on.
Wet particles shall be applied with spray bottles or plastic squeeze bottles to get
gentle even spread. The magnetizing field shall be applied after the particles
have been applied. Flow of particles shall stop with application of magnetic
field.
However wet particles may be applied during the application of the
magnetizing field if they are not applied directly to the examination area and
are allowed to flow over the examination area or are applied with low velocities
insufficient to remove accumulated particles.
10. TECHNIQUE OF MAGNETIZATION
Yoke Technique shall be used. Electromagnetic yokes shall be used to
accomplish magnetization using Alternating Current (AC) only. Care should be
taken to ensure that the legs of the yoke are in good contact with the
examination part and sits squarely and firmly on the part to be examined.
Lifting Power of Yoke – The electromagnetic yoke shall have a lifting power of
at least 10 lbs. (4.5 kg) in AC mode, at maximum pole spacing to be used for
examination. Each weight shall be calibrated and marked with the applicable
nominal weight prior to first use. A weight need only be verified again if
damaged in a manner that could have caused a potential loss of material.
11. MAGNETIC FIELD ADEQUACY AND DIRECTION
Adequacy of the applied magnetic field and its direction may be verified by pie
shaped. Magnetic Particle Field Indicator, which shall be placed on examination
surface such that copper plated, side is away from inspected surface. Suitable field
is indicated when clearly defined lines of magnetic particle forms across the copper
face of the indicator when magnetic particles are applied simultaneously with
magnetizing force. This verification shall be done before each examination.
Kalkars NDT Services, Plot No: 200, KK Nagar, Madurai 625020. TN
Phone: +918144605550, 04522580550.
*For reference only. KNS not responsible for errors & omissions in if any.
